22. Rail gas pressure welding process applicable without specialist welding skills

A common rail welding method used in Japan is gas pressure welding. This technique however requires specialist skills for the rail end surface grinding process and rail heating stage using a burner. A new simplified and standardized gas welding method has therefore been discussed and developed with minimal requirement of specialist skills.

Examination of the rail-end surfaces on newly manufactured rails revealed that the contact surface required for gas pressure welding sufficiently flat, confirming that gas pressure welding can be performed after simply removing any rust with a small-scale grinder. An oscillating pattern for the burner was proposed, which offered sufficient bonding strength, and avoided excessive melting of the rail surface during the heating process. Based on this, a standard swinging operation was set, and an automatic burner swinging device was developed, capable of reproducing the proposed swing pattern (Figure 1).

Tests were performed on the gas pressure welds on a JIS60kg standard carbon rail manufactured according to the newly developed gas pressure welding process (Table 1) to evaluate its performance. Results showed that the performance of the new welding process was equal to that of existing methods.